It is well known in the prior art to impart vibrational waves to filter elements such as filter tubes and filter leaves in order to remove filter cakes deposited thereon during a filtration cycle. When the cake is dried prior to the vibrating operation the operation is sometimes referred to as a dry cake discharge, and when carried out while the cake is wet or while immersed in liquid it is usually referred to as a wet cake discharge. U.S. Pat. Nos. 3,212,643 and 3,867,291 disclose ways in which shock waves have been used in the past to remove filter cakes from filter elements.
While the vibrating systems disclosed in the above patents and known in the prior art have been widely and successfully used, for many applications there is a need for a faster and more complete removal of the cake than has been heretofor attained.